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How much oxygen is put in say a 180-seater A319 or A320 aircraft?
I read the answer in How much oxygen do commercial airliners carry? but it doesn't go into any details about two things:

How much oxygen is carried? I do imagine it would be quite a bit.

How much weight does it have? I am imagining that it probably would be liquid oxygen as that it would be much easier to carry, more compressible, fill everything better than in the gaseous state. I have been reading about liquid oxygen in different contexts hence thought it would be good to ask.

In general, a plane requires enough oxygen to supply all passengers for enough time to descend to ~10k feet. This may be stored as actual O2, or it may be generated when needed by a chemical reaction. This post may answer your question: https://aviation.stackexchange.com/questions/740/where-does-the-oxygen-for-the-emergency-gas-masks-come-from.

It does but only partially. For e.g. I didn't know that the air we breathe when flying high-altitude (only long flights) is the same as outside except it's pressurized via fuselage. It sadly doesn't comment and is too generic as to what actually happens in an emergency. The real reason for which the oxygen is stored. :(

If there was or had been some good maths which told one would have idea of at least how easy or difficult it is both to the pilots and the maintenance staff to keep them in top condition. I do understand it is a sensitive question as theoretically a bad actor or rather actors could make a bad situation and also sabotage the system by filling laughing gas or worse. :(

Yes the air you are breathing in the cabin is outside air compressed by the main engine compressors.  It's compressed to an equivalent altitude of 8000 ft, so it's identical to ambient air you'd breath on an 8000 ft mountain and there is no need to actually add additional oxygen.  The main difference is that the high altitude air will have almost no humidity.

The report of the Quantas flight 30 on 25th July 2008 accident says the passenger oxygen system of Boeing 747-400 has 13×3 256 litres, pressurized to 12 755 kPa. I don't know whether A320 family has compressed oxygen or generators though.

Note that the oxygen is either compressed or generated when needed. Liquid oxygen is not practical, because it constantly evaporates, and it is difficult to work with. Compressed oxygen can stay in the pressurized bottles much longer, and working with pressurized gas tanks is fairly simple (divers typically work with 200 bars, which reinforced flexible hoses handle just fine, and the pressure here is lower than that).

The answer to your question is that it depends on the aircraft, the flight operation, and what you consider onboard oxygen.
MD88Fan and Alan Hudec have pretty well answered your question. Although I think that you have a slight misunderstanding about the oxygen carried aboard any aircraft. To better understand, let us call the oxygen “Supplemental Oxygen”.
The percentage of oxygen in the air is fairly constant regardless of the useable altitude of most aircraft. At higher altitudes, there is just less air. Less air means that there is less oxygen at the same percentage of oxygen in the air. Just as important is the lower pressure of the air. The lower the air pressure, the harder it is for your body to infuse your blood with oxygen.
At higher altitudes, the only ways to keep your blood oxygenated is to increase the percentage of oxygen reaching your lungs, or to pressurize the air reaching your lungs. Supplemental oxygen can do one or both of these, depending on the supplemental oxygen system. As altitude increases even more, it becomes less possible for the body to infuse even 100% pure oxygen due to the lack of air pressure. That is why a continuous supply of supplemental oxygen can be used in non-pressurized cabins up to a certain altitude.
In a pressurized cabin like the one used for the Airbus family of aircraft, the air in the entire cabin is kept at outside ambient air pressure at and below 8,000 feet MSL Pressure Altitude. Above 8,000 feet MSL Pressure Altitude, the aircraft engine compressors will supply air pressure to keep the inside of the aircraft at 8,000 feet Cabin Pressure Altitude. If the system were to fail, supplemental oxygen is supplied only to the passengers and crew, and not to the entire inside of the cabin.
In a failure of the pressurized cabin and or reduction of cabin pressure, the air crew has pressurized and sealed oxygen masks. The cabin is supplied with portable pressurized masks. The passengers are is normally supplied with chemical oxygen generators that should last about 15 minutes. The oxygen supplied is of a high concentration. But, it is at a minimal increased pressure.
This gives the air crew plenty of time to perform an emergency descent down to 10,000 feet MSL or below, where the outside air pressure is enough to make the air inside the cabin breathable. For comparison, Denver, Colorado has an elevation of over 5,000 feet MSL and Vail, Colorado has an elevation of over 8,000 feet MSL.
The only normal exception to the above are aircraft that have flight paths that require extensive time over very high terrain. Aircraft flying in the Himalayas are an example of this. These aircraft will be outfitted with pressurized oxygen masks supplied by pressurized bottles of oxygen for each occupant on board. These bottles take up useable space and payload capacity. But, they are necessary to provide each occupant both the oxygen, the pressure, and the time necessary for the aircrew to find a safe path down to a lower altitude.

I am from India, can you share roughly how much payload capacity may be sacrificed say if the plane was flying above Himalayas. Can happen quite a bit in North and North-East India. All of that area is nothing but the Himalayas, the youngest mountain.

@shirish - Unfortunately, I do not have those specifics. Considering the size of the portable oxygen bottles for the cabin crew, I would imagine that quite a bit of the overhead luggage bins for carry-on baggage would be sacrificed. The extra weight may not effect payload capacity much. But, it would require the taking on of more fuel than would normally be required.

An A320 carries oxygen generators for passengers and cabin crew, pressurized oxygen for flight crew (including observers) and some portable oxygen bottles [1].
I can't find the exact volume of the pressurized container, but it is pressurized to around 1800 psi (124 bar) when full; [2] (page 148) gives minimum pressure for flight and how long for it should suffice.
Average amount of air inhaled by an adult human is usually given around 2 000 l/h, which contains around 400 l of oxygen (at standard pressure). The passenger masks are required to last quarter an hour, so they need to provide oxygen that would have 100 l at standard pressure (but at 0.15–0.2 bar only) per passenger. Plus there are some (around quarter) extra masks for people who are walking in the aisle at the moment decompression occurs.
Only flight crew masks must be able to provide pure oxygen at sea level pressure to be able to keep smoke or fumes out in case those enter the cockpit. These are always supplied from a pressurized bottle, because it must be possible to turn them on and off as they may be used in other cases too (fumes, pilot feeling unwell, preemptively if the pilot is alone for some time etc.) and the chemical generator will release all their oxygen once triggered.

It's VERY rare for an airliner to carry actual oxygen. Most carry chemical oxygen generators that use an exothermic reaction to produce oxygen.

This video explains in detail how the system works. Overly simplified, when you pull down on the mask (and you should pull with some force) you're pulling a pin to start the reaction that generates oxygen for your row of seats on whichever side of the aisle you're on. So if you're sitting in the window seat of a 737 and you pull your mask, you start the O2 generator for the 2 people next to you. However, everyone should pull their mask because it's just a good idea for redundancy.
However, some airplanes DO carry oxygen. Aircraft that fly for extended periods over mountains extending above 10,000ft MSL and there's a point over said mountains at which the aircraft cannot reach 10,000 feet within 15 minutes (or whatever similar limit there may be for a given O2 generator), aircraft may carry oxygen in tanks, which gives more time to get to 10,000 feet. Aircraft that fly over extensive mountain ranges such as the Himalayas are the most likely to have this capability.
General aviation aircraft that are oxygen equipped typically carry tanks, because they're not used for emergencies, but they're used for preventing hypoxia in unpressurized aircraft for extended flight above 12,500 feet.
Carrying oxygen in tanks isn't effective for airlines because they usually don't need to spend a lot of time without pressure. All they need is enough to get down to 10,000 feet, and in most cases, chemical O2 generators provide this capability.
All airliners do carry SOME bottled oxygen, however, it's not for (99% of) passengers. The oxygen available in the cockpit is carried in tanks. There's also bottled oxygen in the aircraft's medical kit. Fighter aircraft have onboard O2 generators, but they're not chemical in nature.
To conclude, the overwhelming majority of commercial aircraft do NOT carry passenger bottled oxygen. While there is some bottled O2 on board, it's not available for passenger use in the case of a depressurization. That's handled by chemical generators.

Despite their (somewhat misleading) name, chemical oxygen generators do "carry oxygen around" just like in a bottle. The difference is that the oxygen is bound in chemical form, not so much in a physical container. The bound oxygen has a much smaller volume than the gas, but the mass of the oxygen atoms remains the same.
A true oxygen generator that doesn't have to carry oxygen with it would be a CO2 splitter, if there is enough CO2 available to process. (CO2 splitting though is very energy intensive and not practical for the purpose discussed here)

B747s sure are more than 1% of airliners, and they carry pressurized oxygen for passengers.

@bogl Sure, but not in the sense that OP intended.

What do you mean? He is asking if oxygen is carried, and what is the weight of the oxygen carried. The answer shouldn't depend on what the OP expects or intends.

@bogl I don't interpret OP's question as including oxygen generators, as they said "I am imagining that it probably would be liquid oxygen" and then "everything better than in the gaseous state". Nothing was included about oxygen generators, which don't even contain O2, rather sodium chlorate and iron powder. While that can create oxygen, contains NO OXYGEN.

Oh dear. Take care!

You as well! I hope I didn't seem too aggressive.

I have just no interest in hair-splitting. If you prefer to think there is no oxygen in sodium chlorate, fine. I have no problem with that.

I see where you're coming from. I suppose I should have said that it reacts to produce oxygen but itself is not pure O2. Ah, well. Hindsight is always 20/20!


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Why are there no RNAV (ILS) approaches?
While studying the PBN (FAA Order 8260.58A) and TERPS (FAA order 8260.3D) documents, I still have some trouble figuring part of the logic behind the naming and definitions of the published IAP Charts. Specifically, I still have not figured out which Lateral Navigation System is combined with which Landing System (if this is how it's done in practice). Take the following examples:

Technically, ILS is a landing system, to the best of my understanding, at least. I expect that it can be combined with any Lateral Navigation System used in-flight, as long as the necessary equipment is available. Therefore, I would expect to find charts using RNAV with ILS. This would mean, to me, that, "RNAV-equipped" flights can still use an ILS Landing System. Is this combination possible?
According to Chapter 3 of the PBN manual, the RNAV(GPS) procedures can also be combined with a GLS Landing System. However, I have not found any published IAP chart mentioning the GLS minima. To my understanding the RNAV(GPS) procedures with GLS Landing System are published separately under the name "GLS". Is this correct?

My confusion can be described, in short, as follows: because I have seen RNAV (GPS) procedures being combined with LPV or LNAV/VNAV, which are Landing Systems, and ILS is also a landing system, I thought that the general idea is that Lateral Navigation Systems are combined with Landing Systems when designing IAP procedures. Is this correct? If yes, where can I find the possible combinations. If no, then what is the logic behind this, what am I missing?

Note that “ILS” on charts always refers to both The localizer (lateral) and glideslope (vertical) together. If referring to one part of the system by itself they use LOC or GS. I’ve never heard of any approach using any type of RNAV for lateral and GS for vertical. Afaik if there’s a GS available there’s always a LOC available.

For TERPS, the naming of approaches is determined by the equipment that is necessary to fly the approach from the FAF to the IAF.  Since RNAV is never required when a localized is used inside the FAF you will never see a RNAV ILS approach  If RNAV, VOR, NDB or DME is required from the IAF to the FAF or MAP to the hold, it will be charted with a note on the plate but it will not be in the title.  Thus you will never see a RNAV VOR or RNAV NDB or RNAV LOC BC approach.  You can see RNAV (GPS) or RNAV (RNP) as those use a RNAV receiver with a specific input.

You are confusing some terminology.
RNAV (GPS) approaches can have several different sets of minima.
See the example RNAV (GPS) Y 28L at O'Hare:
It has:
LPV
LNAV/VNAV
LNAV
sets of minima.

LPV is an instrument approach procedure (IAP) with localizer-type precision and with vertical guidance, (hence the name LPV), provides a pilot with a "ILS-style" approach complete with a decision altitude (DA) but using GNSS equipment instead of VHF equipment like that used for an ILS.  Usually the lowest weather minimum of the 3.
LNAV/VNAV is another line of minima with baro-aided (altimeter-based) vertical guidance including a DA but the weather minimum is usually a bit higher than LPV.
LNAV-only is the least precise of the 3 and is a non-precision approach, no vertical guidance, includes a minimum descent altitude (MDA) instead of a DA.  This is a "dive & drive" approach similar to Localizer or VOR approaches.  Normally has the highest weather minimum due to the nature of non-precision approaches.
There are RNAV (GPS) approaches and there are ILS approaches, but there are no RNAV ILS approaches.
Note: There might be a rare exception to this as described in appendix C of FAA Order 8260.58A CHG 2: If the aircraft/aircrew/airline are performance-based-nav (PBN) capable & authorized there could be an IAP constructed with a radius-to-fix intermediate segment leading to an ILS final segment, whereby, the crew would navigate with GNSS equipment on the RF segment and then transition to ILS equipment for the final segment.  I would say in my experience this type of approach construction from the US TERPS is very rare.
I will add that WAAS is to LPV as GBAS is to GLS.  GLS is only available at 2 airports in the US, while RNAV approaches with LPV minimums are available at a great many US airports, adding a "ILS-like" utility to those airports without incurring the infrastructure cost of adding the ground equipment necessary for ILS approaches.
WAAS capable GPS receivers are prevalent; while very few aircraft (the Airbus A350 is one example) have GBAS capable GPS equipment.

Example of the scenario you describe in your note: Ketchikan, Alaska PAKT ILS Z Runway 11. RF, GPS, DME, ADF all required as well as your ILS receiver! It's still called an ILS though. I think GPS can substitute for the DME and ADF requirements. http://aeronav.faa.gov/d-tpp/1903/06053IZLZ11.PDF until it expires.

Don't even need a RF leg to require GPS/RNAV on an ILS procedure, see the KJAC ILS Z or LOC Z RWY 19 approach plate for example -- it uses a series of linear legs to approximate the intercept turn, avoiding high terrain to the north of the airport and allowing lower approach minima as a result, but requires RNAV 1 (GPS) to fly those legs

The gist of your question is whether it is possible to couple RNAV with ILS? The following ILS chart of Cochin Airport (VOCI) is an ILS approach where Initial and Intermediate approach are executed  using RNAV (GNSS)instead of conventional Navaids but final approach is ILS. Aircraft with RNAV1 capability can execute this approach.

RNAV(GPS) procedures being combined with LPV or LNAV/VNAV, which are
  Landing Systems

Your confusion here is that LPV is a landing system which it is not. It is a way of saying your GPS is going to work kind of like an ILS and will have similar horizontal/vertical responses on your way down or as the FAA puts it

Localizer Performance with Vertical guidance (LPV) approaches take
  advantage of the refined accuracy of Wide Area Augmentation System
  (WAAS) lateral and vertical guidance to provide an approach very
  similar to a Category I Instrument Landing System (ILS).

Similarly LNAV is not an approach system its an idea, again from the FAA.

Lateral Navigation (LNAV) approaches are non-precision approaches that
  provide lateral guidance. The pilot must check RAIM (Receiver
  Autonomous Integrity Monitoring) prior to the approach when not using
  the Wide Area Augmentation System (WAAS) equipment.

LNAV approaches can use various types of instrumentation like a VOR, or a GPS.
When you combine an LNAV approach with some type of vertical guidance you get LNAV/VNAV or LPV. The difference will be how your aircraft is equipped as well as what service level you get. If you have a WAAS capable GPS with good reception you may have the ability to get an LPV approach, if your reception is not as good you may get downgraded to LNAV/VNAV minimums.
In some GPS units you may get a glide slope display even if you are only flying an LNAV approach. This will display as LNAV+V on your GPS unit and means Lateral navigation with ADVISORY vertical guidance. i.e. this glide slope may be safe to fly but is not guaranteed and you need to fly the step down altitudes.

This would mean, to me, that, "RNAV-equipped" flights can still use an
  ILS Landing System. Is this combination possible?

Sort of; It depends what you mean by "use an ILS". There are two way to utilize an ILS system. An ILS provides both lateral and vertical navigation provided you can receive the signals and have a CDI with both lateral and vertical needles. In this case you can fly it down to the ILS minimums.
If you have a receiver/CDI only capable of displaying lateral information you can only fly the localizer approach. A localizer approach uses the lateral component of an ILS with step down altitudes. The altitudes are based on points that are often based on a DME or other radial intercepts.

There are only two airports in the US approved for GBAS approaches and you need some fairly special avionics to fly the approach. GBAS minimums vary depending on operation you can find some more info on that here.

Only one of the previous answers has emphasized the most important misunderstanding in this question. PBN, LPV, LNAV/VNAV, LNAV-Only, etc, are not landing systems. They are criteria by which landing systems are measured and classified. The measurements will determine other criteria like Decision Altitude/Height and Minimum Descent Altitude/Height.
RNAV, ILS, MLS, Localizer, Glideslope, VASI, PAPI, etc, are all landing systems which utilize the above criteria. There is some bleed over between landing systems and navigation systems since RNAV, VOR, and NDB can be used for both.
As far as the question about combining RNAV with other radio NavAid equipment based Standard Instrument Approach Procedure, one only has to look at the Aeronautical Information Manual Section 1-2-3. This allows RNAV to substitute for DME on approaches requiring DME. Also, RNAV can be used to navigate any procedure or to navigate to the Intermediate Approach Leg of any procedure up to but not including the Final Approach Fix (except for DME). Once you reach the Intermediate Leg, you must establish yourself on the Final Approach Course utilizing the navigational equipment prescribed in the approach (allowing for substitution of DME by RNAV).
After the Missed Approach Point, RNAV can be used to navigate the Missed Approach Procedure.

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What is CENRAP?
According to the AIM, in class B and C airspace separation of VFR traffic is "suspended during CENRAP operations":

Separation of VFR aircraft will be suspended during CENRAP operations.
  Traffic advisories and sequencing to the primary airport will be
  provided on a workload permitting basis. The pilot will be advised
  when center radar presentation (CENRAP) is in use.

What is CENRAP, how are pilots informed that it's in use (i.e. what is the radio phraseology?) and what action is expected from pilots in that case?

CENRAP is when an approach control uses the long-range center radars for the separation of their traffic, instead of their normal radars(maintenance, damage, etc). When in this mode, separation standards increase due to the longer rotation/slower update speeds(which allow the longer range visibility) of the Center Radar.
If you ever hear about CENRAP, it'll usually be on the ATIS, or the radar facility probably won't provide services to VFR aircraft, just due to the degradation of radar quality.

CENRAP means Center ENroute RADar Program.  This program was created by ZKC center and then adapted throughout the FAA.  The ARTCC transmits radar coverage data on the interfacility INTO/INTO interface.  Center surveillance comes from multiplte radars.  The Center's coversge area is divided into 16nm x 16nm  boxes called Radar Sort Box (RSB).   Many of these RSBs create what is called mosaic  radar.  Each RSB has multiple radar sites adapted, from best to lesst.
FAA 7110.6B Order says 3nm seperation may be applied for single site radar provided the target is within 40 nm of the antenna.   Beyond 40nm, then 5nm separation must be used.
Because of this order,  multiple radars (mosaic) cannot be used.  Also center radsr is evaluating the target's merit and will dynamically switch to next best radar.  Its possible for the center's software to switch to 4 different radars based on coverage merit.
CENRAP coverage area is adapted by defining which RSBs to use.  Typically a 4 x 4 RSB  is 4x16 or 84 miles by 84 miles.  Also FAA long range radar used 12 second sweeps and  targets are reduced to a 1/8 nm accuracy by the common digitalizer.  Range accuracy is 1/8th nm and termiinal radar is analog providing a smooth coverage.

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What is the asymmetric feature on the rear of a Sukhoi Su-47?
I saw this part on the rear of the Sukhoi Su-47 Berkut, and I can see that it is asymmetric. Is it maybe for interference, or is it a take-off aid because the Su-47 is a STOL plane?
What is it and why is it asymmetric?

Edit:Second picture is mirrored

It's just a thing put there to create asymmetry by someone who was a secret admirer of Burt Rutan.

Is it a reference to the ad-1?


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Is B 737 Max able to comply with certification if MCAS is off or removed?
Boeing 737 Max updated MCAS will probably be cutted off in case of AoA disagree. Without MCAS, the plane is no longer similar to 737 NG (stick force per g requirement). Does that mean a new certification ?

Thanks Bianfable. The question is not about MCAS role (answered by this previous question), but about new certification or not.

So,  that means MCAS must be present and fail-safe ?

I think the linked question answers this. Without MACS the airplane would be terribly difficult to fly by human pilots under certain conditions, but the FAA have formalized rules against difficult to fly airplanes.


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Why do airlines seem to go out of business suddenly?
FlyBMI are currently in the news for failing and stranding passengers abroad. This is not the first time an airline has halted operations seemingly overnight and left passengers without a way to get home.
Why is it that airlines stop operating so suddenly, compared to other businesses which seem to go through a more protracted period of profit warnings, administration... and generally more orderly windup?

Not really on topic, but when businesses are ran at really low gross profit, all costing assumptions need to materialize, else the profit is gone. Some of these assumptions are related to fuel costs, cabin filling rates, and competition prices. If one change, the ticket pricing doesn't float anymore. Only strong and large businesses can take care of passengers whatever happens, including losses.

Welcome to aviation.SE! I'm not sure that your basic assumption here is entirely valid: plenty of other companies go bust and leave their employees, customers and creditors in the lurch. Lehman Brothers was a much larger and very famous example. My guess is that airlines just attract more attention because their customers can end up stuck miles from home or even abroad, which makes for a good news story. It's a bit more dramatic than customers not receiving the socks they ordered, for example :-)

I'd say its quite on topic, as it's about the special procedures the airline business has - not just for pilots.

Mainly because winding down airline business will turn it into a sudden and from there on increasing loss. Airline operation nowadays is calculated in most cases toward a rather high plane utilization. Even more so on low cost enterprises. Sometimes even 10% less passengers may turn a profitable flight into a loss.
Airlines depend on filling up flights - until the last seat and last moment (last minute bookings being, depending on the business plan, even being more profitable). As soon as an airline would announce the intention to close down, new bookings will dry up quick, making next to every flight after this unprofitable.
This all is due the fact that, unlike a brick and mortar store, most cost of an airline are operational cost. There is no valuable inventory to be sold of over time, or much existing machinery to be run until the last moment to convert existing materials in (somewhat) higher valuable products, to turn it into cash. For Airlines there is none (No, collector value of in flight magazines don't really count), so shuting down the flights removes next to all further expenses, stoping any further increase of debt.

Not to mention, that flying after such an announcement would become almost impossible as each and every supplier would demand cash payment from that moment on - with airport fees and fuel payment most prominent - something a money strapped airline hardly can provide. Airlines that tried to go that way usually postponed the shutdown just by days - and often with planes stuck in all corners of the world, unable to return, not able to sell them, but instead adding more debt in airport parking fees.

It might be worth adding to your last paragraph that with many businesses, it's better to go on selling/manufacturing even at a loss, because it might be the most cash you can get from inventory you've already paid for.

Dan: in many countries (probably most of those operating airlines) it's actually illegal to continue trading while insolvent. A receiver can keep going if it will reduce the debt (and probably will, for the reasons in the new paragraph) but not for long.

@TimLymington but as soon as word gets out that the company is insolvent, bookings will slow greatly, so the receiver would have a rough time pressing on.  What they need is for ticket sales to be in trust or escrow, like bank deposit accounts, so the airline must hold all ticket revenue in trust and can't book it as income until the flight actually goes. Then if they cancel, the ticket value could be released to pay another airline to get you home.

Yep. Store or manufacturers can slowly close and earn some many till it’s over. An airline lost all of it customers trust with announcing financial problems. They can only earn some money after going out of business, selling their planes. When everyone works together I nightmare for passengers can be prevent, like done in the case of Air Berlin. But yes, someone has to pay it, in that case german tax payers. And even after that, the temporarily reduction in the number of flying planes made live of everyone more difficult. Even of the surviving competitiors.

@TimLymington Not at all in the United States. Chapter 11 bankruptcy explicitly is designed to allow the company to continue to function and shed debts. Delta was operating under bankruptcy 2005-2007; Air Canada 2003-2004; United 2002-2006; AA 2011-2013; America West (basically the owner of AA and US) 1991-1994, GM and Chrysler went bankrupt in 2009...

Excellent answer. It should be noted that a "10% less passengers may turn a profitable flight into a loss" can happen quickly, especially for small airlines that fly to a limited number of destinations. For example, there is a boycott campaign of Japanese products right now in South Korea and many local companies cancelled regular flights to Japan due to lack of passengers. I would not be surprised if some low-cost company go bankrupt soon.

When you buy an airline ticket, you are buying a promise that at some future date there will be a seat on a plane for you to make your journey. If you have any reason to doubt whether that promise will be fulfilled, the rational thing to do is buy your ticket from a different airline.
That is fundamentally different from many other commercial transactions, where you are buying something that can be delivered right now. If a store chain announces that it may have to close next week or next month, that makes no difference to you if you can physically go to the store and carry what you have bought out of the door. If the shop closes the next day you still have what you bought, and it has exactly the same functionality and reliability as it would have if the store were still trading.

It's actually not that common and is probably mostly related to the bankruptcy law in the country where the airline is incorporated.  Countries that have bankruptcy laws that allow second chance rescue plans like "Chapter 11" in the US (or Company's Creditors Arrangement Act in Canada) typically see the airline go into a bankruptcy process that sees the airline continue as it is reorganized and negotiations go on with creditors.
Certainly in North America airlines almost always go with one of these restructuring/reorganization routes once or twice before they disappear and these sudden collapses don't really happen very often.
A lot of airplane sales happen because an airline in bankruptcy protection is "restructuring" and part of the restructuring plan involves updating the fleet to something is is newer and cheaper to maintain, so word of a Chapter 11 execution is sometimes not bad news for a manufacturer, when the bankrupt company was flying around old beaters and is now shopping for new machines backed by fresh capital or loans.
Possibly FlyBMI has gone through a restructuring already and the options and creditor protections under UK bankruptcy law have already been exhausted.  Usually these things go down the drain slowly, then suddenly, so anyone who was not an insider is caught unawares, like passengers.

According to their union, there was "no warning". My reading is that the shareholders decided to stop covering the losses, and either mgmt didn't have enough time to restructure or their attempts to do so failed. Continuing to operate would just make things worse.


text:
Can a commercial aircraft fly at night with complete navigation and communication equipment failure?
Disclaimer: I know there are numerous redundancies and the complete failure of navigation and communication system may not be possible. Hence, let's approach this question as a pure thought experiment.

If a commercial aircraft is flying overwater (there are no visual markers visible) and there is complete navigation and communication system failure, can a pilot still bring the aircraft back to a nearby airport?
Also, is there a slimmest possibility that this kind of failure is possible? Say, a complete electrical failure including the backup batteries?
Adding more information:

Let's assume commercial aircraft is something like B737, B787, A320, A380, etc.

I am not a pilot, so I don't know if most pilots can navigate using stars, but would love to hear pilots' opinions.

Stars may be present, and even the Moon may be there. But if you are not anticipating that kind of failure, would an average pilot be aware that what direction the Moon is in?

Are there visible stars?

You need to define "commercial aircraft".  Some smaller older, aircraft will have vacuum driven attitude and directional gyros, plus airspeed and altitude.  That would allow an aircraft with total electrical failure to make an emergency descent to visual conditions.  You are correct that more modern aircraft have a lot of redundancy, but once all the backup batteries are exhausted you'd be out of luck.

P.S.  I would interpret "no visual markers visible" to include stars...

If you said to me you were going to take away all of my flight instruments, gryos, airspeed, altimeter etc, except ONE, what would the one be?  Easy. The wet compass.

@MichaelHall I have added more information. Would love to find out if an average pilot can navigate using stars.

That's almost a separate question, but your average pilot cannot navigate by the stars.  At least not in the way we define navigation.  Best you could hope for is to maintain orientation and a general heading to back up the wet compass.  Same for the moon.  Keep it where it is, or make a 180 to go back and put it on the other side.

Complete electrical failure is certainly deadly for "B787, A320, A380" since those are fly-by-wire controlled, so you might want to reduce that to just nav/comm. failure. A B737 could still be controllable with complete electrical failure.

Are we assuming that the GPS & moving map in the pilots' iPads are still working? Those would be good for some reasonable accurate navigation, if that's all you had left.

Possibly related

For the sake of the IFR/In the blind answer, lets assume that for this question at least the backup attitude and airspeed indicators are working and the pilot can in some capacity fly the plane in the blind if need be.
Sure, as long as your failure does not involve some kind of critical flight system failure that would effect the pilots ability to control the airplane. All aircraft are equipped with a magnetic compass which all pilots are trained to use at some point in the training. Magnetic compass' are pretty simple and generally independent of system failure so they are always available for navigation. You can fly across an ocean with a compass pretty effectively (Lindbergh did it...) and all pilots should have the basic understanding of how to do this.
Historically planes were indeed equipped with a sextant and a navigator to use it but you would be hard pressed to find one on a modern airliner or someone who knows how to use it. That being said it can be done, at one point in history it was the norm. There is even a license you can get to officially be a "navigator" although in the modern era is a bit redundant.
So yes, if you lose GPS, INS, GLONASS, radios, HF radios and all manner of everything you can still fly a plane just fine with a stop watch and a compass.
Heres a good resource on old school navigation which has some great info.

EDIT: As noted int he comments, what if the compass fails? Well you have a few options

continue on your present heading until land comes into sight
(also noted in the comments) attempt to use a known star pattern to visually reference direction

And if all clocks on the plane fail, start counting your Mississippi's.

@quietflyer If a pilot has a smartphone handy, I would hope they would use it for GPS rather than googling celestial navigation.

Unfortunately complete electrical failure can (and has) happened: Air Illinois Flight 710. In this flight one engine had a generator failure, and the crew mistakenly shut off the other generator. Eventually the battery failed, and the airplane crashed. Part of the accident report suggested diverting to another airport before the batteries failed.
I would regard getting the airplane to an airport as theoretically possible but unlikely.

This multi-part question contained a question about using the stars or moon to navigate--
Most pilots probably know how to find Polaris, which would be extremely useful, for flight north of the equator, but not too close to the north pole.
The moon (and the constellations of the zodiac) always rise generally in the east and set generally in the west, with "generally" meaning "somewhere between SE and NE, etc, at most latitudes."  Are most pilots aware of this?  Do they know how to recognize the constellations of the zodiac?  Hard to say-- but probably not.
Orion rises with his belt nearly exactly east and sets with his belt nearly exactly in the west. Most pilots probably don't know this either.
Some pilots may have a general awareness of what constellations of the zodiac are due south in the northern hemisphere (or due north in the southern hemisphere) around midnight at certain times of the year, but most probably don't.
The location of a star, or the moon, that is not near the horizon, i.e. has not recently risen or set, is probably not going to be all that helpful to the average pilot.  And directly over the north or south pole nothing is rising or setting.  So-- it depends on a lot of things, including the pilot's level of knowledge about the night sky, and the aircraft's location, specifically the latitude.
In general I suspect the average pilot would be hard pressed to do much more than find the location of Polaris and understand that that is due north, which is really only useful at low to mid latitudes in the northern hemisphere.
Training in recognizing the constellations is definitely not a part of any pilot training curriculum!
This answer assumes the wet compass is unusable due to failure (or due to the aircraft being very near one of the magnetic poles), and focuses on using the stars to determine heading.  If the wet compass still works, then all you need the stars for is for a stable (well, slowly drifting) reference point so you don't have to constantly stare at the wet compass-- any pilot should be able to manage that.  Actually determining latitude with any meaningful precision is not going to be possible without a sextant even if Polaris is visible, and accurately determining longitude is going to be impossible without a sextant, navigational tables, and a precise chronometer.


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Why is the nose cone of the Su-34 white?
The title says it all. It can be clearly seen, for example, in this image:

(image source: Wikimedia)
The rest of the jet seems to have a camouflage.

Tips of the vertical stabs are also white...

Related

@Rodrigo, Now we should probably mark this question a dup of that newer one, because it has a good answer, and the answers are the same for both, and the accepted answer for this Q is incorrect.

@Zeus I would wait a few weeks before making this a duplicate.

@RonBeyer: Stabs tips are white because they are also radomes hosting VHF antennas (3D blueprint).

It is all part of the camouflage.
The blue parts on the bottom make the aircraft hard to identify from below against a blue-background (sky). The dark parts on the top make it difficult to identify from above against a dark background (ground).
The white parts make the aircraft's size/shape difficult to determine. This helps to confuse the enemy by making the aircraft seem farther away than it really is.

totally agreed, in addition to Ron's answer each country has its own camouflage color reference/catalouge lets say. I have found it hard to get the Russian one but you can have a look at the US one here
https://www.milspeccoating.com/Federal-Standard-595-Colors-s/41.htm#products-595

I would think more of a "fade" from grey to white, than a sharp line, would be much better, even if the fade is only over say 6 to 12 inches or so.

https://www.ausairpower.net/Su-34-Fullback/NAPO-Su-34-Fullback-V.Kuzmin-0112-3.jpg I have seen photos of SU-34s with grey radomes and matching vert stab tips. I am not convinced that a bright white radome is considered a form of camouflage. I would like to see some sort of reference to back it up.

I'm with Mike Sowsun.  In fact, highlighting the nose and tail like this would provide a clear reference point that could actually aid one in estimating range.  Maybe this is a training or aggressor version?

I am starting to think the radomes are actually “radio transparent” grey or white as per this modelling website: https://internethobbies.com/products/hataka-hobby-ultimate-su34-fleet-fullback-russian-air-force-paint-set-6-colors-17ml-bottles

Radomes are not 100% transparent to microwaves.  Their loss and other effects of the antennas radiation pattern are minimized in the design, construction, and materials used.  But they are not 100% transparent.

Note that the cover of the rear-facing radar is NOT white..

@SteveSh: Well matching radomes materials have a dielectric attenuation less than 0.2 dB, about -3%. But radomes also include protections against lightning (diverter strips) which may deform the antenna radiation pattern (increasing energy in side lobes)

Agreed.  But in some places engineers would sell their first born for a couple of tenths of dB more sensitivity .

@SteveSh: That's likely why the radomes are white, to get the lowest noise temperature possible.

I'm exhausting my knowledge of radomes here, so do not know how the temperature of the radome affects the noise temperature/noise figure of the radar front end.  The temperature of the radiator element or the front end LNA, maybe yes.  But not the temperature of the the radome.

@SteveSh: When the radome receives energy from the outside (including by friction), it radiates a part of this energy in the inner volume, and some reaches the antenna, this may be expressed as a noise temperature, remember the cosmic background radiation is noise temperature of about 3K. (You can include '@mins' in your message, for notification)

They're white because that's the cove of the radar dome(Radome) by being white, they reflect em interference and thermal suns rays to keep radar clutter to a minimum

I assume the same. Like the black noses of older passenger planes.

The color has nothing to do with whether or not it reflects EM (electro magnetic) interference [signals].  White does reflect solar radiation, which can help reduce sun loading (heating) on the antenna and other electronics behind the radome.

How about the vertical stabs then? Also, the cover of the rear-facing radar is NOT white..

Because they protect sensitive instruments while allowing electronic signals to pass through, nose cones – also known as radomes – must be made from specific materials. These materials often include fiberglass, quartz, honeycomb and foam cores; as well as various chemical resins

@juzzlin - Because there's probably an antenna of some sort on top of the stabilizers.

This answer is the good one. @juzzlin: White radomes at stabs tips are for VHF antennas.

You might want to look at this SE post, https://aviation.stackexchange.com/questions/25368/how-are-antennas-integrated-into-stealth-aircraft.  Everyplace there's an antenna, there's a radome of some sort or other over it.


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Why is the nose cone of Russian fighters pointing slightly down?
Let's take the Sukhoi Su-30 as an example:

The nose cone is clearly pointing a bit downwards with respect to the level of the engines and wings. Why is this? How can this kind of banana even fly properly?
Here's the profile an F/A-18 for comparison:

+1 for calling it a banana.

The nose cone position depends upon the mission profile of the aircraft. Su-30 is a multirole fighter for all-weather, air-to-air and air-to-surface deep interdiction missions, since its air-surface with deep interdiction it needs to have a view of the ground while targeting ground troops/equipments/artillery. This nose down config helps it to have that view. F-18/F-16/F-15 are air superiority aircrafts. Yes same cannot be said for F-18 but then F-18 has many variants, F-18D which has air-ground support is slightly elevated pilot view for better ground view. Same can be seen in Eurofighter Typhoon and A-10 Thunderbolt.
While Su-15, Su-24 and Mig-27 where interceptors and bombers, they have straight nose just like their companions from the west.

Same principle was applied to Concorde nose, due to its long nose pilot wasn't able to see the runway. So they developed a way to lower its nose while taxi. This is beautifully demonstrated in this video (starts at 5:05 ) https://www.youtube.com/watch?v=2oiv4249sRU

I would like to know how this affects aerodynamics.

It makes SU-30 longitudinally unstable or we can say "relaxed stability".

The F-18 is properly the F/A-18, with the A for Attack. Ground attack. It was dual role from its inception, and is not considered a pure air superiority fighter. (Consider the aircraft it replaced...) Also, you don’t strafe from straight and level flight, you dive when attacking the ground, so tilting the nose down to see what you’re attacking doesn’t make sense.


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What is the purpose of a movable inlet on a jet engine?
I was reading that aircraft like the F-15 and SR-71 have movable inlets. What's the purpose of this?
I was also reading aircraft like the F-22 doesn't have a movable inlet. Why?

related: How can an F-22 Raptor reach supersonic speeds without having supersonic inlets?

Jet engines require the air that flows into them to be subsonic. Supersonic air hitting the front fan would cause shockwaves inside the engine, with undesirable results.
So the job of the intake on a supersonic aircraft is to slow down the air to subsonic speeds. The intake is designed to set up a series of shock waves. The air will slow down to subsonic speed as it crosses these shockwaves.
The location of these shockwaves changes with speed: the higher the speed, the shallower the angle of the shockwave and the further the shockwave will reach down the intake duct. So if you have a fixed-geometry inlet, your maximum speed is limited: there is a speed at which the shockwaves will intersect the front fan.
Variable intakes avoid this problem: the movable vanes in the inlet aim the shockwave so it stays in front of the front fan at all speeds. This enable a higher top speed to be reached.
If you accept a lower top speed, you can avoid the extra complexity of a variable inlet. For the F-22, for example, a variable inlet would make it more difficult to maintain a low radar cross section, so the tradeoff was made to maintain stealth and lower the top speed.

Might just want to clarify what you mean by "stays out of the engine at all speeds", as an internal shock system is still inside the engines inlet.

Also, some cool anecdotal evidence of what happens when the intake unstarts: http://roadrunnersinternationale.com/unstart.html

Does the shock wave responsible for slowing air down to subsonic speeds?

I will leave the more accurate answer to someone with deeper knowledge than me, but here is an intuition.
A jet engine needs a certain amount of air flowing through it in order to work. It can't be too much air, and it can't be too little air.
The faster you go, the more air is "rammed" into the engine, just by virtue of you moving faster through the surrounding air. A variable geometry inlet allows you to "shape" the flow of the incoming air such that always the right amount of air is flowing into the engine.
The SR-71 operated from standstill to almost 3.5 times the speed of sound. Now, the sound barrier is particularly interesting, because a normal jet engine requires that the air flowing through it is subsonic. So, the SR-71 in particular had the capability that, by moving the "spike" in the inlet, the engine could transition between a "normal" turbojet engine (subsonic airflow in the inlet and in the combustion chamber) and a supersonic turbojet engine (supersonic airflow in the inlet, but subsonic airflow in the combustion chamber).

Ramjets use just the forward momentum to compress the air and have never been used on human carrying aircraft. The SR-71 (and all other jet powered aircraft) still use an bladed (in this case axial) compressor to compress the incoming airflow. They are just turbojets, but with inlet ramps to slow the incoming air.

This is really interesting. On Wikipedia, it says that the J58 is sometimes wrongly described as a turbo ramjet. And literally in the sentence before that sentence, in the same Wikipedia article, it is described as a turbo ramjet. :-D Well, at least the second sentence is definitely correct: it is sometimes described such, namely in the sentence directly before :-D

I guess it's just a matter of interpretation. The shock system will indeed cause a pressure increase, but the axial compressor is still needed to get the required pressure rise.

I just found it funny that the Wikipedia article first says it's a turbo ramjet and in the very next sentence says that it's sometimes called a turbo ramjet but that is wrong.

I've edited the answer to just call it a "supersonic turbojet".


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Gray cargo prop plane with ∇ or Δ symbol on side and French-like tricolor flag tail?
What type of plane flown today has the following characteristics?

gray body
cargo/freight
4 props
∇ or Δ symbol on side
vertical, French-like tricolor flag on tail's rudder

Welcome to aviation.SE! Can you give us any more information for context, especially where and when you saw the aircraft?

The two possibilities I know of are the C-130 and the A400M. I suspect the latter as shown in this linked photo.

@Gerry Perhaps. I'm not claiming the plane is French. Also, the 3, French-like tricolor (blue, white, red) stripes were vertical on the rudder only, but perhaps these planes have various paint jobs.

When and where was the aircraft observed?

@CptReynolds Yesterday, landing in a civil airport.

@Geremia Well. Which one? At least the country would give a clue, if you don’t want to share actual location... but it would even be better knowing which airport it was!

Did it have a conventional tail (suggesting C-130) or a T-tail (suggesting A400M)?

@Sean I don't recall the tail.


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How do gull wings help?
I know that gull wings are shaped how they are for maximum help with a decrease in induced drag and increase in lift, but how do they do it? This is my homework!!!

I think they were more to get the engine higher off the ground for prop clearance. https://en.wikipedia.org/wiki/Vought_F4U_Corsair

The wings on the Navy 4FU Corsair are actually REVERSE gull wings.  Gliders and real seagulls have them the other way around.  For birds, the anhedralled wing tips would give better roll control in side gusts and make the wing stronger to positive G loading, helping them work the wind to stay aloft.  Possible benefit to a sinking glider may be to "trap" a bit more high pressure under the wing.  They are seen on the Fafnir of Dr. Alexander Lippisch in the early 1930s.  Dr. Lippisch knew a thing or two about gliding.

Gull wings are a solution to two problems.
Requirement for increased speed will require a big propeller. The problem would be the propeller tips would hit the ground. You can solve this by either having longer landing gear (aircraft sits higher) or pushing the engine further out infront.
The problem with longer landing-gear is it needs to be heavier to ensure sufficient strength. Pushing the engine out further increases the overall length of the fuselage, good for stability but not in a fighter which needs to make tight turns.
Looking at the corsair you can see how the forward part of the fuselage is quite long with the engine stuck on the end. I believe this was the most they could do without sacrificing maneuverability. To get additional clearance without a heavy landing gear the gull-wing brought the gear height to a more manageable length.
The second issue is the fact that the Corsair was intended for carrier landings, which meant the landing gear had to be strong. A long landing gear would need to be very heavy to have the required strength. The gull-wing allowed a shorter (lighter) landing-gear.

Aside from the ground clearance thing Crossroads mentioned, the main aerodynamic benefit of gullwings is to achieve a clean 90 degree intersection with the fuselage, which eliminates the need for a big wing root fillet fairing.


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Do all single-engined aircraft experience torque that cause a turning tendency during the takeoff roll?
I've been flying the Cirrus Vision SF-50 for quite some time on my X-plane 11.
Having a single turbofan engine mounted near the V-tail, I expected the requirement of at least a little right rudder. However, it seems to be perfectly aligned throughout the roll.
Why is a turbofan any different from a propeller aircraft in this regard?

Consider the reason that propeller-driven singles have that torque. Would you expect the same effect to apply to a jet?  Also, "do all single engine..." has the answer no, for the case of an engine/propeller that rotates the other way.  The torque in that case is opposite the normal case.  But that's due not to the engine's rotation than to the propeller's.

This might be useful. https://aviation.stackexchange.com/questions/9153/why-do-most-single-propellers-have-a-clockwise-rotation - In Europe, some engines spin the opposite way.

You are overlooking what might be the most obvious explanation: the designers of the simulator may not have modelled the aircraft accurately.

There are four reasons why a propeller aircraft will exhibit a left-turning tendency: torque, spiraling slipstream, P-factor, and gyroscopic precession.
Torque is due to Newton's third law of motion. As the engine spins the propeller, the propeller spins the airplane in the opposite reaction. Since most propellers spin clockwise as viewed from the cockpit, this results in a tendency to roll (and therefore turn) to the left. For jet engines, the rotation of the blades is cancelled by the stator blades redirecting the airflow the other way.
The spiraling slipstream is caused by the fact that the propeller is rotating, causing the air moving through it to also rotate. This spiral flows around the plane, eventually hitting the rudder. Because, again, the engine is rotating clockwise, it will tend to push the rudder to the right, forcing the nose left. Jets don't suffer from this, because, again, the internal stators make sure the exhaust gasses are (mostly) linear.
The P-factor is caused by the fact that the airplane isn't perfectly level. It will usually have a slight nose-up angle. This means that the descending blade has a higher angle of attack, and thus produces more "lift" (a.k.a. "thrust") than the rising blade. Since most engines rotate clockwise as seen from the cockpit, this means that the blade on the right will be the one producing more thrust. Jet engines don't have this because the airflow in the engine is redirected to be parallel to the engine centerline, regardless of the plane's actual angle of attack.
Gyroscopic precession is kind of complicated, so I can't really explain why this happens without a digression into a bunch of complicated physics. Just know that, if you push on the edge of a rotating disk, it will create a force 90 degrees ahead of the point you're pushing on. For a tail-dragger aircraft, lifting the tail is the same as pushing on the top of the propeller disk, thus, precession creates a left-turning force. But then, when either kind of airplane pulls up to take off, this actually causes a right-turning force. Jet engines are no different from propellers in this regard, and will produce these forces in exactly the same way. It's just that the gyroscopic precession in a typical airplane is much, much smaller than the other forces, so the creators of X-plane probably didn't think it was worth programming such a tiny force into the game.

All correct, but you haven't really answered the question. This is true IF the airplane has an engine that rotates clockwise (viewed from behind). If you fly an older (mostly likely European) airplane with an engine that rotates counterclockwise, the factors above will be reversed and the airplane will exhibit a right-turning tendency.

The airplane in the question didn't have a right-turning tendency. It was staying straight without rudder input. So I interpreted it more along the lines of "why doesn't it have a turning tendency at all".

You're right. To avoid nitpicks on "answering the question", I've edited the title to make it clear that I was looking for this answer.

@Gerry except if the engine is in the back (pusher) forces are reversed. The Cirrus Vision is a jet in propeller-land (sky?), guzzling 60-70 gallons per hour. Love the convenient placing of the jet, not much else. X-plane 11 is a simulator, helping hold fuel costs down.

@Robert no, a pusher will have the same tendency for the same rotation direction. (Except that if you mount the same engine on the back, you will effectively reverse its direction). All these effects create torques around the prop attachment point, except for the slipstream. The latter is usually the strongest of all, but on most pushers the tail will be out of the slipstream anyway (and if it wasn't, the yaw torque would have the same direction again).

No wonder they tried the jet mount, guess I'll give the A-10 a look.

Gyroscopic effect is actually fairly intuitive for propellers. Just watch the blade in isolation – if as it passes through the top you nudge it forward, the little bit of forward motion you add combines with its fast motion to the right, changing it's direction slightly instead so it only reaches the forward-most position when on the right.

It's down to resultant torque more than anything else. In propeller-driven aircraft, the propeller shaft is in some way directly coupled to the engine's crankshaft (whether it be through a gearbox of some type or just a direct coupling), which means that the reaction body for any torque required to overcome drag on the prop's blades (which are essentially small wings, like a helicopter's rotor blades) is the engine block and therefore the airframe.
In a pure jet engine of some type (turbofan, turbojet, etc), the shafts are free to rotate. They're mounted to the engine's frame using an assortment of bearings, but there is no other mechanical coupling between them (save for the starter and generator). Compressor blades do still experience drag in the same way as regular prop blades. Huge low pressure compressor ("fan") blades on high bypass engines in particular have been known to go supersonic at the tips under take-off power. Ever wonder why airliners sometimes roar on take off? That's why ;) That means there's still plenty of torque required to keep them spinning. The main difference alluded to above is that this time the reaction body is the turbine. There's VERY little direct torque coupling between rotating bodies (compressor/turbine shafts) and the rest of the engine's construction (just drag in bearings), and a bit of indirect coupling in the form of compressor/turbine stator torque. The latter results mostly in torsional loading on the engine's frame, where the compressor vanes cause torque in one direction, and the turbine vanes cause the opposite. Very little resultant torque ends up transferring into the airframe.
Two special cases are helicopters and turboprop engines. In both cases there's a gearbox involved as turbines are efficient at much higher speeds than both props and main rotors (plus the rotor spins in a different direction). The gearbox, in effect, becomes the reaction body for prop/rotor torque, transferring the reaction into the airframe.

In ultralights and light-sport aircraft with pusher engines mounted in a central location (slightly aft of the CG in the fore-and-aft sense, but fairly high in the vertical sense), it seems that the spiral slipstream is the dominant factor, and it also seems that the vertical fin mainly experiences the LOWER half of the spiralling slipstream, especially if the vertical fin is not very tall (e.g. the Challenger ultralight aircraft.)  That is the only way to explain how an prop that rotates clockwise (as viewed from behind) would generate a right turning tendency in such an aircraft, as is very often the case.  Take a look at the fixed (bendable) trim tabs on the rudder in such aircraft-- if the prop rotates clockwise as viewed from behind, they are usually bent toward the right, to move the rudder toward the left and generate a left yaw torque.  If the prop rotates counterclockwise as viewed from behind, they are usually bent the opposite way.
Clearly, in such a case, it could happen that at some airspeed and angle-of-attack, P-factor (which would generate a yaw torque to the left if the prop rotates clockwise as viewed from the rear, regardless of whether the prop is ahead of the CG or behind the CG or in line with the CG) could exactly counteract the rightwards yaw torque from the lower half of the spiralling slipstream striking the vertical fin.
So it is undoubtedly not true that all single-engined aircraft (with propellers) experience a turning tendency at all airspeeds and angles-of-attack encountered throughout a take-off roll and climb.

Just noticed the question was about a turbofan-powered aircraft!  Oh well...

"Leftward Torque" or left-turning tendencies only affects piston engine aircraft. In order to understand why this doesn't happen to turbofan aircraft, you have to know what causes these left-turning tendencies.
There are actually four different reasons why this happens: Torque, P-Factor, Spiraling Slipstream, and gyroscopic precession.
Torque is the reaction of the airplane to the rotation of the propeller as it turns clockwise (from the pilot seat), the airplane will want to turn the opposite way which is to roll to the left.
P-Factor is because the propeller moves clockwise so the descending blade will have higher AOA than the ascending giving more thrust from the right resulting in left yawing. This is noticed mostly during a climb.
Spiraling Slip Stream is because the wind generated by the prop rotates around the aircraft and hitting the left plane of the rudder resulting in left yaw.
gyroscopic precession is very complicated but it affects conventional geared airplanes more than tricycle.
All these forces except for gyroscopic precession, which is very minimal, only affects aircraft with propellers. P-factor doesn't have an effect because turbofans have blades, not propellers. Also, turbofan engines are ducted so spiraling slipstream will not be a factor. And the torque is canceled out by the turbines at the back of the engine.

Although this answer is mostly right, there are a few major errors. Left-turning tendencies also affect turboprop airplanes, they're not restricted to piston engines. Also, the "blades not propellers" argument is flawed; "blades" would also be affected by P-factor in exactly the same way as the blades of a propeller if the airstream was coming in at an angle.


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Identify Aircraft in Petra Album Art

Was listening to one of Petra's old songs, when I noted the aircraft in the cover image. I tried searching on the net, but couldn't find anything.
It appears to be a pusher aircraft, with a four blade propeller.. that's all I could gather from the image. There are markings "ANG" (?) but I do not know how helpful that is.
This is from Petra's album titled "Beyond Belief".

It is a C-130 Hercules.  Of the four engines , the only feature prominently visible is the outboard left propeller.
I'm not sure why you thought it might have a "pusher" configuration-- the nose is to the left (off the edge of the photo), and vertical tail (with the "ANG" logo) is showing near the center of the photo.
Other prominent features are the flap attached to the trailing-edge of the (left) wing, and the (lit-up) back end of the fuel tank attached below the left wing between the two engines on that wing.

The reason I thought it was a pusher was that the half of the aircraft with ANG inscribed seemed to be too short to be the rear of the plane, and I was seeing things sorta out of proportion. After you pointed it out, yes, that part is actually the tail. Thanks for the fast answer! C-130 it is.

ANG is most likely a reference to "Air National Guard".

@Milwrdfan -- agreed--

@WilliamR.Ebenezer - funny thing.  When I looked at the photo, just the same as you, that appeared to the front of the plane (ie on the right) for some reason!

What I really want to know, is what's with all the water all over the floor?

@quietflyer looks like the aircraft is outside and we are looking into the hangar. Picture was taken at night with the hangar lights on. Exposure makes it look brighter inside.

@quiet flyer, when it comes to night shoots & paved areas, directors of photography can't stop themselves from a  having a "wet-down" for wide shots. It helps with lighting, & the contrast & reflections look great. It's a stylistic touch that goes back to the early days of cinema. It doesn't even need to be night time, you'll often see extremely wet roads in movies, but nothing else will be wet, not cars or roofs,& nobody will be wearing wet weather gear. The paving will be shiny with puddles because it was hosed down just seconds before the cameras rolled.

@WilliamR.Ebenezer -- funny how the viewing screen makes such a difference-- on my laptop, if I held it at the right angle I could clearly see that the left outboard engine nacelle blocked part of the external (underslung) fuel tank from view-- on my phone screen the image is too dark to discern that-- on laptop, tilting the screen to change viewing angle has an effect like changing contrast on photo-- not on phone screen--

@quietflyer Yes I have seen this kinda stuff happening before. Different colors appear relatively different on different devices.. for instance, my Samsung phone makes colors (and audio XD) more vivid. However, the screen-tilting contrast variation doesn't come on my laptop (I have noticed this on other laptops though) - I guess there's some anti-glare built in.


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In the Lockheed Martin Flight Services system, what are MIFR, MVFR, YFR and ZFR flight rules?
When I file a flight plan I can file under either IFR or VFR flight rules. However, the Lockheed Martin Flight Services website has the following options in addition to IFR/VFR:

MVFR
MIFR
YFR
ZFR

1 and 2 are only available for US domestic flight plans; 3 and 4 are only available for ICAO plans. What are all these options and when should I use them?

I'm pretty sure Y and Z are VFR-to-IFR and IFR-to-VFR flight plans, I can never remember which is which though.

@CGCampbell It's actually explained on the LMFS website, I just hadn't noticed that the "flight plan" heading was also a link...

@Pondlife Aha! I see that now. Excellent discovery. Odd how they use Military VFR, contra to the well-known (and potentially misunderstood as well) defined use of MVFR.

According to the tooltips on the Lockheed Martin site, the flight rules are:

MVFR - Military VFR; restricted to military flights
MIFR - Military IFR; restricted to military flights
YFR - Initially operated under IFR, followed by one or more changes of flight rules
ZFR - Initially operated under VFR, followed by one or more changes of flight rules

There's very little information on MVFR and MIFR flight plans that I could find, but the FAA's FSS procedures do include specific actions that are required when receiving a military flight plan (section 6-4-7).
YFR and ZFR are ICAO rules; the FAA calls combined VFR/IFR flight plans composite flight plans (see section 5-1-7 in the AIM) and on a US domestic composite flight plan both VFR and IFR should be checked. Interestingly, the Lockheed Martin site doesn't allow that.

On the off chance someone stumbles upon to this years later and is interested in knowing more on the military flight plans...
I was a civilian ATC in a few facilities handling a lot of military traffic. The military flight plans we received were largely the same, with a few exceptions. One instance in which I can see FS wanting to be told up front that it is MVFR or MIFR is if they are using a stereo route - a commonly used, set route that is coded for brevity in clearances. For example, ROUTE1 could represent ABC-DEF-GHI.
There are a few other differences, but that's one informed guess.

MVFR: Minimum/Marginal Visual Flight Rules
This refers to the general weather conditions pilots can expect at the surface. MVFR criteria means a ceiling between 1,000 and 3,000 feet and/or 3 to 5 miles visibility.1, 2
YFR
Flight initially being IFR then going VFR3
...or...
Flights that will initially will be operated under IFR, followed by one or
more changes of flight rules.4
ZFR
Flight initially being VFR then going IFR3
...or...
Flights that will initially will be operated under VFR, followed by one or
more changes of flight rules.4
MIFR: Multi-engine IFR5

1: NOAA National Weather Service
2: YahooAnswer
3: PilotsOfAmerica
4: ForeFlight
5: Canadian Fight Center

You're correct about the normal meaning of those acronyms, but that's not what they mean in the context of this question.

@reirab Thanks for the downvote. I already know the context of the question and have talked with the OP about doing more research. Please post an answer with what they mean in the context of this question and I'll delete mine.

There's already one above.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Does an airport need to have at least one instrument approach that I can use in order to fly IFR to it?
Half Moon Bay (KHAF) does not have any instrument approaches into the airport that I can use. All the approaches require RNAV but my aircraft is not RNAV-capable. Can I fly IFR to it?
I'm thinking that if weather is good, ATC can clear me for the visual approach.
If weather is bad, I'm thinking that they wouldn't be able to clear me and would ask me for an alternate airport to land at?

KHAF does appear to have 4 instrument approach procedures.

@Dave-CFII good point. I forgot to put in my post that in this scenario my aircraft is not RNAV capable, which all the instrument approaches require.

Under Part 91, you can file IFR to any point in space, including an airport without an instrument approach. But that doesn't mean you'll be able to land there.
FAR 91.175(a): "Unless otherwise authorized by the FAA, when it is necessary to use an instrument approach to a civil airport, each person operating an aircraft must use a standard instrument approach procedure prescribed in part 97.."
What ATC can do is clear you to that point in space at their lowest vectoring altitude there. If, when you arrive, the conditions are VFR, you can cancel your IFR and land. If not, you have to go somewhere else, possibly the alternate airport you would be required to have filed in your flight plan. And it's that alternate airport that MUST not only have instrument approaches, but have weather forecasts and reports high enough to meet the alternate minimum requirements of 91.169(c).

You don’t need to cancel your IFR clearance. You can remain IFR and ask for a visual approach. That way if conditions aren’t as expected (e.g too windy, fog rolls in, runway is icy) you can get back into the IFR system and go to an alternate.

Well it depends on the forecast weather at the destination.  If the airport is forecast to have VFR conditions at the ETA, then an instrument approach procedure is not necessary.  If conditions are forecast to be MVFR or worse at ETA, then at least one approved instrument approach must be available to the pilot per §91.175.
While those are the legal guidelines, remember the SAFE-LEGAL-REASONABLE rubric for making a go-no-go decision.  While it may be safe or legal to fly IFR to an airport with no instrument approach if the weather at ETA is forecast to be VFR, it does close off one avenue of escape should something go wrong.  If you do intend to do this, I would include a nearby airport as an alternate in your flight plan.  This alternate should be equipped with both precision and nonprecision approaches, whose minimums are above that forecast for the alternate at ETA, with the appropriate fuel reserves.


text:
What is the proper phraseology for a clearance with a named obstacle departure procedure?
The Phoenix Mesa-Gateway Airport (KIWA) has a named obstacle departure procedure - the Phoenix Departure.
What's the correct phraseology for when clearance assigns it to you? Is it "N123AB, cleared to XXX, via the Phoenix Obstacle Departure"?

I bit of trivia about the naming. You may have noticed that departure procedures all have a number associated with them (and most have one or more transitions). You will never find a Phoenix One and a Phoenix Two. Whenever a departure procedure is changed, the number is incremented. It’s quite rare to find one that is still numbered 'One'. At this airport most of them are up to Six and one is Seven.

@JScarry after Nine they cycle back to One, if the procedure has not changed enough to require renaming.

Items in parentheses on these charts are not said when referring to them by name. It's the same for other departures/arrivals that are RNAV, and for approaches that may be GPS or RNP.

This is an Obstacle Departure so this is not assigned by ATC.  Some obstacle departures are textual based and some have an image depiction of the departure, such as this one.  Part 91 pilots are not required to follow Obstacle Departures under an IFR flight plane but it is highly encouraged.  Commercial flights must follow Obstacle Departure procedures and it is up to the pilot in command to seek them out and fly them not for ATC to assign them.
More information on IFR departure procedures can be found here.

ODP must be followed under part 91, according to 91.175 (f) (3).

The difference between part 91 and 135, 121 is that part 91 operations do not need to follow takeoff minimums 91.175 (f) (4).

It's called the "Phoenix One Departure", exactly as depicted in the title.  Why do you think it would be something else?

I think the OP is asking for the clearance phraseology, not just the name of the procedure.

It's the same answer either way.  (As a general rule we call things by their name...)


text:
What are the consequences of throttling up past 100% of N1?
The B737 is probably my favorite aircraft and I'm always sure to never throttle past 100% of N1. I was told the aircraft is pretty much totaled if you take N1 past 100% but you can eke out that extra power for emergency purposes. Is that true? What are the consequences of exceeding 100% N1?
And what numbers should I be paying attention to for takeoff in a 737?

See Ralph J's answer to Why isn´t TOGA thrust always 100% N1 or N2?

Please tell us that this isn't for real world flying, but rather a home computer simulator or something like that. If it really is about flying such an aircraft in the real world, then the obvious question becomes: What has your instructor told you when asked about this?

Welcome to aviation.SE!

Your real question here should not be about a specific speed but about a specific thrust level. (see the comments)
Every engine will have 2 ratings a takeoff thrust rating and a maximum continuous thrust rating.
Takeoff thrust is self-explanatory.  That's the level at which you can takeoff.  The engine will only be rated for a few minutes continuously at takeoff thrust.  After that time, you are supposed to reduce thrust.
Maximum continuous thrust (aka "max con" or MCT) is the thrust level at which the engine manufacturer will certify that you can operate for any length of time with no significant impact to the engine.  Max con will be above cruise but below takeoff.  For example, if one engine fails on a two engine plane, you'll need to run the other engine higher than a normal cruise thrust.  Max con is the level that you will want to run at.
In other words, you can go to max con forever, but you can only go above max con (up to takeoff) for X minutes (where X is 5 or, depending on the engine)
So, what happens if you exceed max con thrust for more than X minutes?  If you go a little bit past max con for a few seconds, probably nothing happens. If you go well past max con for several minutes, you can shorten the service life of the engine. i.e. you might have to take the engine off wing and overhaul it a bit sooner than you otherwise would have. The higher you go and the longer you sit there, the worse it will be. And if you go to full throttle for an extended period of time (hours), then you could total the engine.
One of the driving factors of the engine's life is the high pressure turbine.  Problems there are low cycle fatigue, creep, and oxidation.  All of these are made worse when the turbine gets hot. And the more thrust you are making, the hotter it will get. And the longer you sit at high power, the hotter it will get.

The consequences are always explained in the flight manual. It has graphs which specify what you should do if you exceed the speed, temperature, etc., by how much and for how long. For example (this is for FJ33-5A):

Note that the 100% mark is, in a sense, arbitrary. It does not necessarily mean the absolute max (even the 'normal' max), as can be seen from the example. (I don't know how it is for CFM56). This happens for several reasons; typically, the 100% value corresponds to a fixed RPM number for the whole family of engines. As the engine undergoes modifications, the permissible RPM may increase (or, in some cases, decrease), yet the 100% RPM number is usually not changed, moving the red line instead. In some cases, a civil engine is installed on a military aircraft, and is then allowed to run at, say, 108%, at the cost of much reduced lifespan and service intervals.

Sorry, could be wrong here, but given the thermo-resilience of the materials most engines are made from are essentially exceeded by overclocking for to long, the thermo-residue buildup eventually end up melting the engine; this is why there is redundancy built into the MCT for engine outage scenarios etc.


text:
Do airlines require aptitude tests or other similar tests for new pilots?
Do airlines require pilots to take an aptitude test? Are there any other similar kinds of tests that airlines perform?

What kind of test do you have in mind? Airlines are businesses.  Perhaps you mean airline crews, who are humans?

Many airlines also make applicants do psychometric tests as well, as in personality tests.

Perhaps someone would list the kinds of testing airlines perform, and what airlines do what types of testing.

Yes they do, and so do some independent training organisations. For instance EPST markets an aptitude test called Compass, developed to test the suitability of candidates before they engage in pilot training.
Some airlines only hire self funded students (who have paid for their own CPL, type rating etc) and they can be flight tested in the simulator.


text:
Model for flutter analysis of Aerofoil
Why is a aerofoil modeled by attached torsional and linear spring in a  wing flutter analysis.The model does not even satisfy the boundary condition of zero displacement of wing at point of attachment to fuselage. I am considering the pitch plunge model as shown in figure.

Because what you are simulating is not a wing, but an aerofoil at an arbitrary $y$ station along the wing.
The linear spring simulates the wing bending and the torsional one its torsion about the elastic axis. The constants would of course be of the type $k_{e}=f(y)$.

how does this help us analyse a real world airplane flutter case?

you can adjust the constants of those springs to study a specific wing section, which is good enough for the level this preliminary study. More importantly, it already exhibits some of the crucial properties of flutter, like torsional divergence above a certain $U_{\infty}$. Though you should really refine your question, this is just my offhand remark to your initial overly broad query.


text:
Is the lift vector reversed during inverted flight?
Heard a physics professor say that when an aircraft flies inverted, the wing assumes a significant angle of attack (by pushing the stick forward) to continue to generate the necessary "upward" lift vector to maintain level flight. I'm confused. I thought the lift "vector" is actually reversed and points towards the ground (not upward) during inverted SUSTAINED straight-level flight? What am I missing here? The horizontal stabilizer is basically an inverted airfoil, and its "lift vector" points downwards, giving the airplane tail-down force. How is the wing any different when it's inverted?

Actually your use of the term "straight and level" did automatically imply "sustained", but thanks for making it more explicit.

In sustained horizontal inverted flight, the wing is generating a skyward lift force.  In most aircraft the pilot will be exerting a significant "push" force on the stick or yoke, causing the stick or yoke to be well forward of the position it would be in level upright flight at the same airspeed (or at any airspeed for that matter.)  Regardless of the airfoil of the horizonal tail, it is capable of creating an upforce in the aircraft's reference frame when the elevator is sufficiently deflected.  Due to downwash from the wing, the required deflection may be less than you might otherwise expect.
Most horizontal tails have symmetrical airfoils.
"How is the wing any different when it's inverted?" -- the position of the elevator is key.  With sufficient forward stick deflection, the top of the wing rather than the bottom will be presented to the airflow.
Even a flat-bottom, curved-top airfoil can sustain inverted flight in this manner.  Examples are Gentle Lady and Radian radio-controlled model sailplanes, which I'd guestimate can sustain a glide angle of 20 degrees below the horizon or better in power-off inverted flight, given that they are set up with sufficient elevator travel.  It is also possible to demonstrate constant-altitude sustained inverted flight in a radio-controlled model airplane with only moderate engine power (e.g. not capable of a sustained vertical climb) even with flaps strongly deployed (about 45 degrees) in the usual direction in the aircraft's reference frame.  Again, one key is to have sufficient elevator travel.
Remember, in unaccelerated linear flight, net force must add to zero.  The forces in sustained linear inverted flight are weight, thrust, drag and lift.  The vector sum of these forces could never be zero if the wing were generating an earthwards force.
Remember also that (except for apparent forces created by rapid rotation rates perceived by a pilot sitting far from the CG) the force a pilot "feels" in flight is nothing other than the net aerodynamic force generated by the aircraft, which is normally dominated by the lift force generated by the wings.  As you hang in the seat belts during sustained inverted flight, that force you feel from the seat belts digging into your shoulders is really the skyward force generated by the wings.  Conversely when you feel the seat bottom pushing lightly against you as you float over the top of a loop at a reduced but still positive G-loading, that is really the earthward force generated by the wings.

This is easiest to understand with a fully symmetrical wing, which indeed are popular with aerobatic aircraft.  The direction of "lift" has nothing to do with sky or ground and everything to do with your angle of attack to the relative wind.
When inverted, you simply (as the professor said) push forward on the stick, which makes the wind strike the "top" of your wing.  Inverted, this does the trick as lift is now towards your floor, but gravity is toward your head.
Right side up, you make the wind strike the bottom of your wing by pulling back on the stick.

Got it. Super easy to understand if the wing is symmetrical. I'm just so used to thinking that air that goes over the top of a cambered airfoil produces a downwash that creates an "upward" lift force. You're saying that this downwash can also occur even at the uncambered side of the wing while inverted?

@PatrickSpalding - It sure can -- the airfoil of my "Gentle Lady" radio - controlled sailplane is flat on bottom, curved on top, yet it can fly inverted.  Comes down fairly steeply, maybe glide angle is 20 degrees below horizontal, but it can do it.  Ditto for "Radian" rc motorglider with power off.


text:
What make and model of aircraft is this?

Saw this sitting derelict on the ramp at KIDA recently.  The configuration, landing gear, a tail, etc. looks very much like a Beechcraft King Air C90, but the windows aren’t typical of that kind of aircraft.  It also does not match up with the appearance of a Beech C89 Queen Air or a C99 commuter, either.

N200MH is a 1969 Fairchild Merlin IIB, aka Swearingen Merlin.
More registration data is here, including the 2030 expiration of its certification, so it might not be all that derelict.  Flightaware reports a flight in 2021.

Thanks. I in fact did an N-number check just after posting that and found that.  I had never heard of the type before.  And the aircraft really does not look much like what you usually think of a Merlin/Metroliner.

It's at least moderately derelict: the tires are flat.

No tie-downs.  Because it's too heavy to need them??


text:
What is the minimum runway width for SSC Stratolaunch?
What is the minimum runway width for the Scaled Composites Stratolaunch vehicle?
Is this determined by the separation between its fuselages (and thus undercarriages), or its outer engines (to stop blast kicking up soil, and causing FoD)?

They tested it from KMHV which has three runways. 60, 100 and 200ft wide. My guess would be that they used the widest, but I can't say for certain.

A 200ft runway would likely be approved for Stratolaunch, but it would need special approval.
Minimum runway width is determined by both physical characteristics as well as flight performance of the aircraft. A pilot has to be able to safely land the aircraft in adverse weather, cross wind, etc. Since the flight characteristics of Stratolaunch have not been determined, it would not be approved for other than special use operation on any runway at any airport. Even runways that can accommodate such a large plane may not be approved if associated taxiways are not also suitable.
ICAO has a standard table used for determining minimum runway width based on aircraft reference field length, wing span and gear spacing. Stratolaunch is larger than the largest standard entry, so it would not qualify for even 60m/200ft width on that basis.

Looking at the A380 introduction there was interest is allowing operation from 150ft wide runways. FAA Engineering Brief 65A determined that an average pilot could safely operate an A380 on a 150ft wide runway. Its track width is 47ft, so a 50ft deviation on either side was deemed acceptable. If you assume that Stratolaunch is as controllable as an A380 (which I think would be extremely permissive) and given that its track width is just over 100ft, it would be borderline ok for a 200ft runway based on flight characteristics.

The A380 also had a requirement for a "stabilized shoulder", which was intended to prevent runway contamination by FOD. This requirement added a 50ft strip to each side of the runway. Since the span to outer engines is 168ft, the stabilized width was 40ft outside the engines. Stratolaunch engine span is 220ft, so adding 40*2 feet of stabilized surface makes total width 300ft. This is pretty standard for a 200ft runway.
It seems on the basis of this special approval for the A380, a 200ft runway would be approved for Stratolaunch.


text:
What are the reflective structures above and to the rear of the engines on a VC-25?
In this video at 7:04 we see the following view of a VC-25 (an aircraft frequently known as "Air Force One"):

What are the two shiny, gold-coloured structures above and to the rear of the engine exhaust?

According to a comment on the video from Jamie Lancaster:

Behind the engines under the wing are the 2 IRCM (Infrared Counter Measure) Jammers - for Air to Air or Ground to Air Missile Defense.

In the comments below, GremlinWranger suggests that it's likely a descendant of the Common Infrared Countermeasures Program based on the appearance of the ALQ-144, which does indeed have similar mirrored panels.
A bit of further searching turns up this blog entry which claims to show pictures of the AN/ALQ-157 which is even more similar looking, particularly in its four-facet design with hemispherical coverage. (That page also has a reduced-size German poster explaining "Air Force One," by which they mean the V-25, but the relationship of that to anything else in the article is never explained.)

Not an answer since cannot find a photo to confirm but most likely a descendant of https://en.wikipedia.org/wiki/Common_Infrared_Countermeasures_program, see the appearance of the earlier non LASER version https://en.wikipedia.org/wiki/AN/ALQ-144

AN/ALQ-204 Matador
https://cryptome.org/eyeball/af1-ircm/af1-ircm.htm
It is a countermeasure system against infrared guided missiles.
It is a descendant of AN/ALQ-144 and similarly is designed to defeat first gen man portable air defence systems(MANPADS)

There's quite a bit of information in the (excellent) link you gave that would be worth putting in this answer. And this answer isn't really stand-alone yet; it doesn't even mention that this is a missile defense system (it expects readers to know what a MANPAD is to figure that out). If you're willing to expand this to be a stand-alone answer that will briefly explain to people without military knowledge what this is, I'd happily make it my accepted answer. (Or I can expand it if you don't want to.)


text:
Definition of long-haul flight
Who determined the definition of what a "long-haul" flight is?
By implication, this presupposes definitions of "short-haul" and possible "medium-haul"/"extra-long-haul" flights, as I've seen the terms used.
I understand the tag long-haul has a definition of

A long distance flight that lasts six hours or longer.

but I'm curious as to where this definition comes from, and if there's a common authority that different airlines/orgs use to talk about such categories?
For context, a lot of places I've been looking at recently refer to anything over 3 hours as "long haul" (which I see as mildly absurd, since most of my trips include a 12+hour leg).

I edited your opening sentence since you answered the first part of that question yourself in the 3rd paragraph. I've boiled it down to just the part you don't seem to know. Please edit again if I misunderstood something.

Well not really - that tag has a definition, but other common definitions are 3, 8, 10, 12+ hours; I don't know, which is why I'm asking.
We have been looking at kid-flight stuff and a lot of sites are saying 3+ hours is long haul; there's a long way between 3 and 17 hours! We'd never call our 4-5 hour flights long.

Are you asking about the tag definition at this site (if so, this question belongs on meta, not here), or asking about who in the industry determines what "long haul" is?

Who in industry and what that definition is? Or a summary of the various quoted figures and who/why they are thus.

Don't tell me down here, [edit] the question to make this explicit so that everyone reading the question doesn't also have to try to read your mind.

Fair point. On some sites it's bad form to redefine the question after acceptable answers are posted, unless they don't adequately answer the question (eg because it was poorly stated).

If your comment defining what you're looking for invalidates the answer given, why did you accept that answer? If it doesn't invalidate the answer, then editing the question just clarifies and justifies why you did accept it. :shrug:

There is no single definition of what long-haul exactly means!
You are asking for a definition from a common authority. This would typically be ICAO (International Civil Aviation Organization). However, as far as I could find, ICAO does not define the terms "short-haul" or "long-haul". The Wikipedia article on Flight length claims that ICAO defines short-haul to mean anything below 8 hours of flight time1 and long-haul to mean 8-16 hours of flight time, but the linked sources on Fatigue Risk Management Systems do not support such a claim. The term "Ultra long range operations" is however defined in this context to mean more than 16 hours of flight time:

Ultra long range operations (ULR)
Augmented long range operations involving any sector between a specific city pair in which the
planned flight time exceeds 16 hours, taking into account mean wind conditions and seasonal
changes (as defined by the Ultra long range Crew Alertness Steering Committee, Flight Safety
Foundation (2005). Flight Safety Digest 26.)

(FRMS Implementation Guide for Operators)
Another common authority is IATA (International Air Transport Association). They are more concerned with the passenger aspect of air travel. They use the following definitions for EDIFACT and XML messages for data exchange between airlines:

FHT Flight haul type

Long-haul 6 hrs plus
Medium-haul 3-6 hrs
Short-haul up to 3 hrs

(IATA EDIFACT AND XML CODESET, archived)
Other official authorities may define the term "long-haul" for specific documents. For example, EASA (European Aviation Safety Agency) once used the following definition in a Safety Directive:

Definitions:
Long haul flight: Any flight, or series of flights where passengers and their luggage are not fully
disembarked, involving commercial air transport of passengers and lasting 6 hours or more,
measured from the time the aircraft is scheduled to move from its parking position at the beginning
of a (series of) flight, to the time the aircraft is scheduled to reach its parking position at the end of
a (series of) flight.

(EASA SD 2020-04)
Other authorities also distinguish based on length of the route rather than flight time, e.g. Eurocontrol uses

short-haul routes (routes shorter than 1500 km) [...]
medium-haul routes (routes between 1500 and 4000 km) [...]
long-haul routes (routes longer than 4000 km)

(Eurocontrol: Study into the impact of the global
economic crisis on airframe utilisation, archived)
All of these are official authorities in their respective area of responsibility, and even they cannot agree. If you then ask an airline, what their definitions are, you might get answers based on aircraft type:

Lufthansa classifies its fleet as: long-haul for wide-body aircraft [...]; medium-haul for narrow-body aircraft [...]; and short-haul for regional jets [...]

or based on geographic region:

Air France defines short-haul as domestic, medium-haul as within Europe/North Africa and long haul as the rest of the world.

The Wikipedia article on Flight length has many more such examples. There simply is no single definition!

1 Note that flight time is defined by ICAO to include the block-off time on ground:

"Flight time" : The total time from the moment an aeroplane first moves for the purpose
of taking off until the moment it finally comes to rest at the end of the flight.

(ICAO ADREP 2000 taxonomy)

Thankyou, this is exactly what I was looking for!
Apparently according to some sources, in my thousand or so hours in the air, I've taken maybe 1 short-haul flight?!